1. Field of the Invention
This invention relates generally to the field of portable electronic devices capable of generating vibratory alerts.
2. Description of the Related Art
Many portable electronic devices utilize a tactile alert (i.e. vibratory alert) to alert the user of alarms, errors, or incoming data, messages, or calls. The vibrator, upon activation, generates vibrations which are transferred to the portable electronic device housing causing the device housing to shake, thereby alerting the user.
Typically, a vibrator mechanism is an electromagnetic or piezo electric driven rotary or linear device with an off set weight to generate a vibratory sensory pulse. When the portable electronic device is positioned against the user's body, such as by placement in a shirt pocket or hung from a belt, the vibration alerts the user without others hearing the alert. This silent alert is particularly advantageous in meetings, in libraries, in offices where a lot of people share common space and other places where it may be inappropriate to use an audio alert.
Some portable electronic devices today have interchangeable battery packs that allow the end user to trade up to a thicker/heavier device for more battery life (or visa versa). One drawback to this battery pack flexibility is that since the vibrator motor strength (normally proportional to vibrator motor speed) is optimized to one particular battery pack (with its own specific mass), suboptimal vibration performance is observed when thicker (and/or heavier) battery packs are installed.